1. Field of the Invention
The present invention relates to vehicle ramps. More specifically, the present invention relates to vehicle ramps stowable within the vehicle. Even more specifically, the present invention concerns stowable ramps which are used for loading vehicles and which are useful as working tables.
2. Description of the Prior Art
The usefulness of providing loading ramps for small vehicles such as pickup trucks, vans, or trailers has long been known within the art. For example, in U.S. Pat. No. 1,699,882, there is disclosed a vehicle fitted with two stowable skid bars, one on each side of the loading deck of the vehicle. According to this patent, a collapsible skid plate is folded and fitted as a tailgate for the vehicle. When a loading ramp is desired, two skid bars are moved from their location and placed in position with one end of the bars on the loading surface or ground and the other end on the bed of the vehicle. The collapsible skid plate is then unfolded and rested upon the skid bars.
The disadvantages of the skid plate loading ramp becomes apparent when trying to load heavy items with small casters or heavy items without casters. These items are generally slid up the ramps and may become caught at the gaps or off-sets existing at the intersections of the ramp loading surface sections. At each location, the person or persons using the ramp must lift the item over the gaps and off-sets. Also, the ramp has no other support in the loading position, except for the skid bar. This limits the weight of an object that can be loaded using the ramp.
Loading ramps have included single piece ramps stowable beneath a stowing deck. For example, U.S. Pat. No. 4,078,678 teaches a single piece ramp which is stowable beneath a false floor or deck fitted within a van. The ramp is stowed beneath a false floor until it is to be used. When it is needed, the ramp is pulled from beneath the floor until rollers on each side of the ramp seat themselves into a locking notch provided in the supports on each side of the false floor.
The single ramp of this invention reduces the number of gaps or offsets which would otherwise trap heavy objects loaded by sliding or rolling them up the ramp. However, there are several disadvantages with this type of ramp. Because of their location, the locking wheels act as a pivot point and the ramp may see-saw when an object or a user moves from one side of the pivot point to the other. Also, because of the pivot location, the end of the ramp nearest the false floor becomes off-set and may require substantial lifting to move an object from the ramp to the false floor. Further, the single locking points of the ramp only provide for an automatic lock when the ramp is extended. When the ramp is stowed, it is not locked in place, it can move forward and backward unless the van rear doors are closed to stop the movement.
Another type of stowable loading ramp includes telescopic ramps. U.S. Pat. Nos. 4,601,632 and 4,900,217 are examples of telescopic ramp assemblies. Essentially, they teach an assembly which includes a chamber or sleeve and a telescopic loading ramp which is stowed within the chamber when not extended. In both of the above-inventions, the loading ramps, when extended, have two sections. One section is the long section which rests on the ground or loading surface. This section is connected to a second section which usually rests on the tailgate or a bed of the vehicle when the ramp is extended.
When the ramp is stowed, the first section slides into the second section. Both sections, then, slide into the stowing chamber or sleeve. In both of the above-inventions, when the ramp is extended it is automatically locked in position within the chamber by stops or studs located on each side of the second section of the ramp which engage locking slots on each side of the stowing chamber. When the ramps are stowed, manually installed locking pins hold the ramp in their stowed position.
Both ramps have many of the same disadvantages as the previously cited ramps. Because the ramps are telescopic, there is no smooth loading surface. Several off-sets or gaps exist which interfere with the sliding and rolling of heavy objects up the ramp. There is no automatic two-way locking of the ramps. It is automatically locked only when extended. Manual locking is required when the ramp is stowed. Both inventions use heavy strength metal to provide the strength needed during use. This makes them heavy and hard-to-handle during extension and stowing.
Another example of a stowable ramp is U.S. Pat. No. 4,624,619. This invention discloses a stowing chamber with a two-section loading ramp. When the ramp is extended, it is automatically stopped by two pins, extending from the top of the ramp. The pins strike a bumper rail on the stowing chamber when the ramp is extended. When the ramp is stowed, manually inserted pins hold it in place.
There is an angled strip attached to the end of the stowing chamber between the top surface of the chamber and the top surface of the loading ramp. This, apparently, is to ease the transition between the two surfaces. The angled strip has its disadvantages. The angle is steep and short. This still makes sliding or rolling heavy objects up the ramp difficult.
Other disadvantages are apparent: the gap between the two ramp sections is large; the ramp is manually locked in its stowed position; there is no additional support for heavy loads.
This type of loading ramp is usually designed to be used by one person. Therefore, there is a need for a ramp that is easy to handle, limits the amount of user interaction, provides a secure and usable surface to easily load and unload heavy objects which can be slid or rolled on wheels and can be used as a secure work table or the like. It is these to which the present invention is directed.